Effects of lead on avian thermoregulation in the heat: An experimental test with pied crows (Corvus albus)

Andrew E McKechnie; Marc T Freeman; Ryno Kemp; Kerri Wolter; Vinny Naidoo

doi:10.1016/j.etap.2024.104519

Effects of lead on avian thermoregulation in the heat: An experimental test with pied crows (Corvus albus)

Environ Toxicol Pharmacol. 2024 Sep:110:104519. doi: 10.1016/j.etap.2024.104519. Epub 2024 Jul 24.

Authors

Andrew E McKechnie¹, Marc T Freeman², Ryno Kemp³, Kerri Wolter³, Vinny Naidoo⁴

Affiliations

¹ South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, South Africa; DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, South Africa. Electronic address: andrew.mckechnie@up.ac.za.
² South African Research Chair in Conservation Physiology, South African National Biodiversity Institute, South Africa; DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, South Africa.
³ Vulture Programme (VulPro), Plot 121, Rietfontein 0216, South Africa.
⁴ Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, South Africa.

PMID: 39059727
DOI: 10.1016/j.etap.2024.104519

Abstract

Many of the negative physiological effects of lead involve the hypothalamus, but the possibility that thermoregulation is affected has received little attention. We tested the hypothesis that lead exposure reduces avian thermoregulatory performance under hot conditions in pied crows (Corvus albus) experimentally exposed to lead in their diet. Crows in our high lead treatment (blood [Pb] = 87.3 ± 44.7 μg dL^-1) showed significantly higher air temperature (T_air) inflections for evaporative water loss (EWL) and resting metabolic rate (RMR) compared to control (6.4 ± 1.8 μg dL^-1) or intermediate (53.9 ± 23.7 μg dL^-1) lead groups, which did not differ. EWL, RMR and body temperature (T_b) all increased more rapidly at T_air > T_b in the high lead treatment. In contrast, neither maximum T_air tolerated by the crows nor maximum T_b varied with treatment. Our data reveal that water and energy balance during hot weather is affected by lead exposure.

Keywords: ecotoxicology; evaporative cooling; heavy metals; hyperthermia; pollutant.

MeSH terms

Animals
Basal Metabolism / drug effects
Body Temperature / drug effects
Body Temperature Regulation* / drug effects
Crows* / physiology
Female
Hot Temperature*
Lead* / blood
Lead* / toxicity
Male
Water Loss, Insensible / drug effects

Substances

Lead